Storage-battery separator and method of producing same



Patented Feb. 17, 1925.

GODFREY STEEBUP, OF CHICAGO, ILLINOIS.

STORAGE-BATTERY SEPABATOR AND METHOD OF PRODUCING SAME.

, N 0 Drawing.

ing to the sequoia family. When the wood' is in good condition and freefrom such physical defects as knots and pin holes, and when properlytreated chemically to remove constituents injurious to the battery, itwill give fair service for a limited time provided the battery is notover-charged, but high concentration of the battery acid and hightemperatures are ruinous to wood separators. Each of these conditions isoften met with in the lead battery used for starting and ignition andconsequently wood separators used in such batteries graduallydisintegrate and become useless for the intended purpose. Theinefficiency of wood as a bat tery separator will be indicated by thechanges apparent if a wood separator is subjected to a few cycles ofcharge and discharge in sulphuric acid of specific gravity 1.285 to1.300. Other materials, such as glass, clays, vulcanized rubber andfabrics 111 a variety of forms and shapes have been used but withoutsatisfactory results.

The most important causes of failure of the separators which have beenused are (1) the chemical nature of the material is not such as toresist the combined action of temperature and acid; and (2) the physicalstructure of the separator is not of proper porosity and structuralflexibility to permit the diffusion and the circulation of the ionswithout a physico-chemical disintegration.

The object of my invention is to provide a storage battery separatorwhich will stand up in battery acid at any tem rature which mightreasonably be expect in a battery, which can be easily shipped, andwhich will not be affected by climatic conditions.

A further object of the invention is to provide a separator having asubstantial degree of elasticity, which can be produced at comparativelylow cost by molding, pressing, rolling or otherwise and in any shape,size or form, which is comparatively soft and Application filed Inch 27,1922. Serial No. 547,206:

pliable and which will give greater service than any other separatorsknown to me.

The invention further consists in the method of producing my improvedseparator.

For my separator I use unvulcanized rubber and a porous siliciousmaterial and I have found the following to be a satisfactory method ofproducing the separator:

250 grams of a good grade of rubber gum, such as Para gum, or itsequivalent suitable for the purpose, is partially dissolved or jellifiedcold with 7000 c. c. of carbon tetrachloride. To 3000 c. c. of thisjelly is added 600 'rams of diatomaoeous earth, such as kiese lguhr, orits equivalent suitable for the purpose, and which has absorbed 2000 c.c. of water. I prefer that the silicious material shall have beensuitably puri fied as by. floating it with water and separating it andremoving the heavier particles. The mixture of jellified gum andsilicious material is kneaded thoroughly while 300 grams of driedsilicious material is being added, the whole forming a dough-like andhomogeneous mass. ThlS mass may be molded or pressed in separator moldsor it may be rolled or otherwise formed into sheets from which theseparators can be cut or stamped, or it ma be formed into separators ofany size, s ape and form in any other suitable manner and with anysuitable means. The separators can be made immediately after the doughis produced or the dough may be rolled into sheets and shipped in thisform so that the separators can be cut, stamped or otherwise producedfrom the sheets for the manufacture or for the repair of batteries asand wherever desired. I contem late producing these sheets of anydesired tiickness and I believe that from inch to inch will besatisfactory for this purpose. or the sheets may be dried by optionalmethods and the evaporated tetrachloride saved as, for example, bydrying in the atmosphere at a temperature at or below 100 C.; or bydriving off the tetrachloride by steam, followed by air drying; or bydriving off the carbon tetrachloride b immersion in hot water followedby air d rying.

My improved se arator has certain characteristics which (iistin ish itfrom other separators; it is soft to 5 1 c touch, suggestive of chamoisskin; it is pliable and elastic; it

The finished separators and in the handling and use thereo and it alsoenables the separator to better stand the action of the hot batteryacid.

I have found in practice that Para gum and a diatomaceous earth, such askieselguhr, in or about the proportions mentioned, produce verysatisfactory results but I do not limit myself to these particularmaterials but reserve the right to use any equivalent therefor whichwill produce the same or substantially the same results; and I alsoreserve the right to change the pro rtions of the ingredients as ma bedesire to suit conditions as they arise in the trade.

I claim:

1. A separator for storage batteries comprising a homogeneous mixturehaving a substantial proportion of unvulcanized rubber in itscomposition.

2. A separator for storage batteries comvprisin a omogeneous mixturehaving substantia proportions of silicious material and unvulcanizedrubber in its composition.

3. A se arator for storage batteries char: acterized y a high liquidabsorbing quality and comprising a homogeneous mixture of a siliciousmaterial and unvulcanized rubber.

4. The herein described method of producing a material for storagebattery separators which consists in mixing unvulcanized rubber gumpartially dissolved or jellified with a silicious material saturatedwith water and working the mixture into a homogeneous mass and thenreducing the mass to a form from which separators may be produced bymolding, pressing, stamping or otherwise in desired shapes.

5. The herein described method of producing a material for storagebattery separators which consists in partially dissolving or jellifyingunvulcanized rubber gum cold with carbon tetrachloride and then mixinthe same with a silicious material saturated with water, and thenworking the mixture into a homogenous mass and reducing the mass to aform from which separators may be cut or otherwise produced.

The herein described method of producing a material for storage batteryseparators which consists in partially dissolvin or jellifyingunvulcanized rubber gum an mixing the same with a silicious materialsaturated with water; kneading the mixture and adding dry siliciousmaterlal to form a doughlike homogeneous mass; and then reduclng themass to a form .from which separators may be cut or otherwise roduced.

7. The herein described met 0d of producing a material for storagebattery separators which consists in partially dissolvin or 'ellifyingunvulcanized rubber in col wit carbon tetrachloride and mixing the samewith a silicious material saturated with water; then working the mixtureand adding dry silicious material to form a doughlike homogeneous massand then reduclng the mass to a form from which separators may be cut orotherwise roduced.

8. The herein describe method of producing a material for storagebattery se arators which consists in partially dissolving or i'ellifyingunvulcanized rubber cold witi carbon tetrachloride in or a ut theproportions of 250 rams of gum and 7000 c. c. of carbon tetrac loride;mixin the partially dissolved or jellified gum w1th diatomaceous earthin or about the proportions of 3000 c. c. of gum to 600 grams of earthcontaining 2000 c. c. of water; working the mixture and addingapproximately 300 grams oi d diatomaceous earth to form a dou hli e themass to a form from which separators may be cut or otherwise roduced.

GODFR Y STEERUP.

omogeneous mass and then reducing

